Question

Two charges ±10 mC are placed 5.0 mm apart. Determine the electric field at (a) a point P on the axis of the dipole 15 cm away from its centre O on the side of the positive charge, as shown in Fig. 1.18(a), and (b) a point Q, 15 cm away from O on a line passing through O and normal to the axis of the dipole, as shown in Fig. 1.18(b).

The electric field due to a dipole at a distance r on its axis is

If Ea be the electric field strength of a short dipole at a point on its axial line and Ee that on the equatorial line at the same distance, then